Such cutting inserts are known for instance from DE-A 22 31 631, DE-B 23 09 443 and the DE 31 48 535 C2.
DE-A 22 31 631 describes a cutting tool with chip breaker, with a cutting blade attached to the basic chip-breaker body and with a groove running parallel and next to the cutting blade, wherein at least one projection shaped like a truncated cone is provided at a point located close to the nose-like part of the basic chip-breaker body.
According to DE-B 23 09 443, in the chip-breaker groove a plurality of chip-breaking projections is provided, consisting of sphere segments arranged at intervals.
However, due to the arrangement of the chip-forming elements and the geometry of the chip-breaking groove, the mentioned cutting insert can be used only within a limited range of different cutting conditions, such as different cutting depths, advance speeds, and materials. In order to increase the range of use of the cutting insert and to improve the formation and removal of the chips, DE 31 48 535 C2 has proposed to give the chip-forming elements the basic shape of a truncated pyramid, with an essentially triangular base surface, whereby at any time one of the lines defining the base surface is oriented in the direction of the neighboring cutting edge, either parallel thereto or in a curved line.